It has long been known to use different data structures to store data within a data-base. These structures afford various advantages with respect to used storage space and the possibility of fast-searching, for instance.
A known structure is based on a B-tree, thereby enabling the logical distribution of elements in a table within a data-base.
An element may include an internal address in a data-base that is coupled to an external key, such as a telephone number, for instance. When inserting a new telephone number in a table, a calculation is made as to the element in which the internal address of the telephone number shall be placed, by means of a logic order.
The function of the B-tree is to distribute the addresses in the table, so that said addresses are distributed in a manner which will enable them to be easily found.
The B-tree is used essentially to create an ordered and simple structure.
Each tree commences with a root-node which points to further nodes in which a search for a desired node can be carried out on the basis of certain criteria. These nodes will often include a key or an index.
Http addresses, file names, time stamps, telephone numbers, etc., are examples of keys stored in a B-tree.
It should also be mentioned that the aforesaid nodes are nodes in a tree-structure intended to describe an hierarchy of stored keys or indexes, and not processor nodes in a distributed data-base.
It is also known in the case of logically sequential data sets to store solely the difference information between two mutually sequential data sets.
This procedure is used, for instance, in image processing where a large quantity of information is required to store and reproduce moving pictures or images, but where the difference between two mutually sequential images may be very small, and consequently only the difference between these images is stored and utilised when reproducing the images.
It is also known to store solely the difference between two interlinked elements instead of storing the entire element, in conjunction with linked lists.
This requires less storage space, but provides the same information.
It should also be mentioned that in conjunction with file names or http addresses for instance, different formats and suffixes are used which can make it difficult to describe the difference information between two adjacent nodes in a simple manner.
The following publications describe the handling of information structured in a B-tree. "Transaction Processing: Concepts and Techniques", J. Gray, A. Reuter, Morgan Kaufman, 1993 .
"Prefix B-trees", R. Bayer, K. Unterauer, ACM Trans. on Data-base Systems, Vol. 2, No. 1, pp. 11-26, 1977.
It should also be mentioned that it is known to store different elements in a so-called container, where the elements lie consecutively one after the other, and where a container can be treated as a unit.